INAKHOS (or Inachus) was a River-God of Argolis in the Peloponnesos, southern Greece.

The Inakhos River flowed south through western Argos, emptying into the Argolic Gulf between the towns of Argos and Tiryns. Its stream ran dry in mid-summer. Three other Argive streams were personified:the stream Erasinos and two small tributories of the Inakhos, the Asterion and Kephisos. The most important neighbouring rivers were the Asopos in Sikyonia to the north, the Ladon of Arkadia to the west, and Eurotas of Lakedaimonia to the south-west

ENCYCLOPEDIA

I′NACHUS (Inachos), a river god and king of Argos, is described as a son of Oceanus and Tethys. By a Melian nymph, a daughter of Oceanus, or, according to others, by his sister Argeia, he became the father of Phoroneus and Aegialeus, to whom others add Io, Argos Panoptes, and Phegeus or Pegeus. (Apollod. ii. 1. §§ 1, 3; Hygin. Fab. 143, 145; Tzetz. ad Lycoph. 177; Schol. ad Eurip. Or. 920, 1239; Ov. Met. i. 583, &c., 640, &c., Amor. iii. 6, 25; Serv. ad Virg. Georg. iii. 153.) Inachus is the most ancient god or hero of Argos. The river Inachus is said to have received its name from the fact of Inachus throwing himself into it, at the time when Zeus, enraged at the reproaches which Inachus made on account of the treatment of Io, sent a fury to pursue him. (Plut. de Fluv. 18.) The river had before borne the name of Carmanor or Haliacmon; and as Inachus was the first ruler and priest at Argos, the country is frequently called the land of Inachus. (Eurip. Or. 932; Dionys. i. 25; Hygin. Fab. 143.) In the dispute between Poseidon and Hera about the possession of Argos, Inachus decided in favour of Hera, and hence it was said that Poseidon deprived him and the two other judges, Asterion and Cephissus, of their water, so that they became dry except in rainy seasons. (Paus. ii. 15. § 4, &c.; comp. Apollod. ii. 1. § 4.) The ancients themselves made several attempts to explain the stories about Inachus: sometimes they looked upon him as a native of Argos, who after the flood of Deucalion led the Argives from the mountains into the plains, and confined the waters within their proper channels; and sometimes they regarded him as an immigrant who had come across the sea as the leader of an Egyptian or Libyan colony, and had united the Pelasgians, whom he found scattered on the banks of the Inachus. (Schol.ad Eurip. Or. 920, 932; Sophocl. ap. Dionys. l. c.)

Source: Dictionary of Greek and Roman Biography and Mythology.

INACHUS FIRST KING OF ARGOS & THE CONTEST OF THE GODS

Pseudo-Apollodorus, Bibliotheca 2. 1 (trans. Aldrich) (Greek mythographer C2nd A.D.) :
"To Okeanos and Tethys was born a son Inakhos, after whom the Inakhos River in Argos is named. By Melia, daughter of Okeanos, he had sons named Phoroneus and Aegialeus."

Pseudo-Apollodorus, Bibliotheca 2. 13 (trans. Aldrich) (Greek mythographer C2nd A.D.) :
"He [Danaus] went to Argos . . . The land was without water, thanks to Poseidon, who, in anger at Inakhos for testifying that the region belonged to Hera, had dried up even the springs."

Pausanias, Description of Greece 2. 15. 4 (trans. Jones) (Greek travelogue C2nd A.D.) :
"The oldest tradition in the region now called Argolis is that when Inakhos was king he named the river after himself and sacrificed to Hera. There is also another legend which says that Phoroneos was the first inhabitant of this land, and that Inakhos, the father of Phoroneos, was not a man but the river. This river, with the rivers Kephisos and Asterion, judged concerning the land between Poseidon and Hera. They decided that it belonged to Hera, and so Poseidon made their waters disappear. For this reason neither Inakhos nor either of the other rivers I have mentioned provides any water except after rain. In summer their streams are dry except those at Lerna."

Pausanias, Description of Greece 2. 22. 4 :
"Poseidon inundated the greater part of the country [of Argos] because Inakhos and his assessors decided that the land belonged to Hera and not to him. Now it was Hera who induced him to send the sea back."

Pausanias, Description of Greece 2. 16. 4 :
"Homer in the Odyssey mentions a woman Mykene [eponym of Mykenai] . . . She is said to have been the daughter of Inakhos and the wife of Arestor in the poem which the Greeks call the Great Eoiai."

Pseudo-Hyginus, Fabulae 124 :
"Kings of the Achaeans. Phoroneus, son of Inachus."

Pseudo-Hyginus, Fabulae 143 :
"Inachus, son of Oceanus, begat Phoroneus by his sister Argia, and he is said to have been the first of mortals to rule."

Pseudo-Hyginus, Fabulae 274 :
"Phoroneus, son of Inachus."

Nonnus, Dionysiaca 36. 127 ff (trans. Rouse) (Greek epic C5th A.D.) :
"What second Inakhos has awarded her city to Hera?"
[N.B. This is an allusion to the story of the contest of Poseidon and Hera for Argos.]

Nonnus, Dionysiaca 39. 38 ff :
"Once it is said among the Argives that Earthshaker [Poseidon] made water dry, and a horse’s hoof left prints of the dust of river Inakhos dried up."

Aeschylus, Prometheus Bound 635 ff :
"Prometheus : It is for you, Io, to grant them [the Okeanides] this favor [i.e. to tell them her story], especially since they are your father's [i.e. Inakhos'] sisters . . .
Io [tells her story] : Visions of the night, always haunting my maiden chamber, sought to beguile me with seductive words, saying : `O damsel greatly blessed of fortune, why linger in your maidenhood so long when it is within your power to win a union of the highest? Zeus is inflamed by passion's dart for you and is eager to unite with you in love. Do not, my child, spurn the bed of Zeus . . .' By such dreams was I, to my distress, beset night after night, until at last I gained courage to tell my father [Inakhos] of the dreams that haunted me. And he sent many a messenger to Pytho and Dodona so that he might discover what deed or word of his would find favor with the gods. But they returned with report of oracles, riddling, obscure, and darkly worded. Then at last there came an unmistakable utterance to Inakhos, charging and commanding him clearly that he must thrust me forth from home and native land to roam at large to the remotest confines of the earth; and, if he would not, a fiery thunderbolt would come from Zeus that would utterly destroy his whole race. Yielding obedience to such prophetic utterances of Loxias [Apollon], he [Inakhos] drove me away and barred me from his house, against his will and mine; but the constraint of Zeus forced him to act by necessity. Immediately my form and mind were distorted, and with horns, as you see, upon my forehead."

Parthenius, Love Romances 1 (trans. Gaselee) (Greek poet C1st B.C.) :
"From the Lyrkos of Nikainetos and the Kaunos of Apollonios Rhodios [two Alexandrian Greek poets C3rd B.C.]: When Io, daughter of King Inakhos of Argos, had been captured by brigands, her father Inakhos sent several men to search for her and attempt to find her. One of these was Lyrkos the son of Phoroneus, who covered a vast deal of land and sea without finding the girl, and finally renounced the toilsome quest: but he was too much afraid of Inakhos to return to Argos and went instead to Kaunos [in Asia Minor]."

Diodorus Siculus, Library of History 5. 60. 4 (trans. Oldfather) (Greek historian C1st B.C.) :
"Not long after this Inakhos, the king of the Argives, since his daughter Io had disappeared, sent forth Kyrnos, one of his men in high command, fitting him out with a considerable fleet, and ordered him to hunt for Io in every region and not to return unless he had got possession of her. And Kyrnos, after having wandered over many of the inhabited parts of the world without being able to find her, put ashore in Karia on the Kherronesos [and settled there]."

Ovid, Metamorphoses 1. 583 & 639 ff (trans. Melville) (Roman epic C1st B.C. to C1st A.D.) :
"One is absent [from a gathering of the River-Gods of Greece], Inachus, withdrawn deep in his cave and weeping tears that swell his current, as he mourns in bitter grief Io, his daughter lost. He cannot tell whether she lives or dwells among the shades, and finding her nowhere thinks she must be nowhere and fear feeds fear when knowledge fails. Io returning from her father’s stream had caught Juppiter’s [Zeus’] eye . . . [Hera interrupted their rendeavouz, and so Zeus disguised Io in the form of a cow. The goddess was not fooled and demanded it for a gift, and appointed Argos Panoptes as guard.]
She [the cow-shaped Io] reached her father’s river and the banks where often she had played and, in the water, mirrored she saw her muzzle and her horns, and fled in terror from the self she saw. The Naides did not know--not even her father knew who she was, but she, disconsolate, followed her sisters, followed her father, let them stroke her, offered herself to be admired. Old Inachus picked grass and held it out; she licked her father’s hand, cow-kissed his palms; her tears rolled down; if only words would come, she’d speak her name, tell all, implore their aid. For words her hoof traced letters in the dust--I, O--sad tidings of her body’s change. `Alas, alack!’ her father cried, and clasped the moaning heifer’s horns and snow-white neck. `Alas, alack!’ he groaned : `Are you the child I sought through all the world? Oh, lighter grief you were unfound than found. You give no answer; silent, but from your heart so deep a sigh! A moo--all you can say--is your reply! I, knowing naught, made ready for your marriage, hoped for a son-in-law and grandchildren. But now the herd must find your husband, find your child. For me death cannot end my owes. Sad bane to be a god! The gates of death are shut; my grief endures for evermore.' As they thus grieved, Argus, star-eyed, drove off daughter from father, hurrying her away to distant pastures."

Valerius Flaccus, Argonautica 4. 374 ff (trans. Mozley) (Roman epic C1st A.D.) :
"[Io transformed into a heifer was driven from Argos by an Erinys :] Then departing gave she last kisses to her father’s [Inakhos'] banks; wailed [her sister Naiades] Amymone, wailed Messeis’ waters, wailed Hyperia with arms outstretched to call her back . . . Wandering she [Io] comes even to the waters of Inachus, how faring and how changed from that first heifer that she was! Nor do her father or the frightened Nymphae try to draw nigh her."

Nonnus, Dionysiaca 3. 257 ff (trans. Rouse) (Greek epic C5th A.D.) :
"There is a city of Argos, famous for horses, and Hera’s habitation, the midnipple of the island of Tantalides. There a man begat a daughter, and a beautiful daughter,--Inakhos, famed burgher of the land Inakhian. A templeman he was, and brooded over the awful rites that spoke the voice of the divine cityholder, he chief and eldest in practice of her mysteries : aye, he refused to wed his daughter to Zeus lord of the gods, leader of the stars, all for reverence of Hera."

Suidas s.v. Io (trans. Suda On Line) (Byzantine Greek lexicon C10th A.D.) :
"Inakhos, a king of Argos, founded a city which he named for the moon, Io, for that is what Argives call the moon. He also had a daughter Io; Pekos who is also Zeus abducted her and fathered a daughter, Libya, by her. And Io, lamenting her ruin, fled to the Silpion Mountain and there died. Her father and her brothers, when they learned this, built a shrine to her and called the place Iopolis and remained there until the end. And they performed a ritual in her memory, banging on each other's doors every year and saying 'io, io!'"

GOD OF THE RIVER INACHUS, MISCELLANY

Aeschylus, Libation Bearers 7 ff (trans. Weir Smyth) (Greek tragedy C5th B.C.) :
"[Orestes, standing before the grave of his father, speaks :] `I bring a lock to Inakhos in requital for his care [i.e. as the protector of youth], and here, a second, in token of my grief [for his father].'"

Aeschylus, Fragment 84 Xantriae (from Scholiast on Aristophanes, Frogs 1344) :"For the Nymphai Kreniai (nymphs of the springs), the glorious goddesses mountain-born (oressigonoi), I beg a dole, even for the life-giving children of Inakhos, the Argive river."

Plato, Republic 381d (trans. Shorey) (Greek philosopher C4th B.C.) :
"[From Plato's critique of the portrayal of gods by the poets :] No poet then my good friend, must be allowed . . . in any tragedy or in other poems bring in Hera disguised as a priestess collecting alms `for the life-giving children of Inakhos, the Argive stream.' [Quoting the lost Xantriae of Aeschylus.]" [N.B. The children of Inakhos are the Naiad nymphs.]

Callimachus, Hymn 5 The Bath of Pallas 49 ff (trans. Mair) (Greek poet C3rd B.C.) :
"For mingling his waters with gold and with flowers, Inakhos will come from his pastoral hills, bringing fair water for the Bath of Athena."